rotate object list (with different origins) around a single pivot Animation Nodes
You didn't show the render, so it's a little bit confusing to see what you want to achieve and ask, especially you change the question as well at the end. So if I understand incorrectly your question, please point that out.

I think maybe your are looking for the node called "matrix math".
A matrix is like an object, it contains "translation (similar to transform)", "rotation", "scale".
Matrix math currently only contains "multiply operator". The name may sound very confusing, but it allows to transform each individual matrix (ie. object).


Two images are used to states the difference between matrix math and transform matrix.
matrix math works on object's own pivot. Transform matrix works on "world origin".

There are many operator that's only available to a matrix but not a vector. Such as "replicate matrix". So sometimes it may be preferred to "compose a matrix" for distributing objects, or simply use "distribute matrix" node for doing so.

Back to the most beginning, instead of using circles' vertex, you may simply use "distribute matrix", if you really are just looking for a circle.